The invention relates generally to respirators, and in particular to a novel headpiece and mask release mechanism.
Respirators are worn by persons subjected to unpleasant or noxious environments. A common type of respirator is the half mask respirator, which comprises a cup type mask supported by a yoke attached to two sets of straps. One set of straps, the upper set, is designed to rest on the crown of the head of a wearer. The second, lower, set is designed to wrap around the back of the neck of the wearer. The upper set is generally attached to a broadened flexible strap, commonly known as a cradle, that fits over, or cradles, the crown of the head. The upper strap is generally adjustably attached between the facepiece and cradle by a buckle having an adjusting mechanism such as a D-ring for tightening the strap against the head. A D-ring, as is well known in the industry, generally requires that a wearer use two hands to manipulate the D-ring to adjust the length of the strap during donning or doffing often proving to be challenging to the wearer. The lower strap generally includes a fastening element including a hook and slot arrangement and further includes an adjustment mechanism such as a D-ring.
A wearer typically puts on (dons) the respirator by clipping the lower straps behind the neck and then lifting the cradle up onto the top of the crown while simultaneously guiding the mask and yoke portion, or facepiece, into position on the face. The straps are then manipulated through the D-rings and adjusted until a good fit is achieved and a successful face seal check is performed. Removal, or doffing, of the respirator is performed opposite the donning operation wherein the lower straps are unbuckled and the cradle is removed from the head while the facepiece is withdrawn from the face of the wearer.
In the course of an average day, a worker required to wear a respirator may don and doff the respirator up to 20 times. The donning procedures of current art respirators, including adjustment and face seal check, are viewed by many wearers as being complex and cumbersome. In some cases wearers forego the donning procedure when it is perceived that the task they are to perform would take less time than the donning procedure. The donning procedure is further complicated by other protective equipment such as goggles, glasses, earmuffs, hats and hard hats that need to be removed in order to don or doff the respirator.
The doffing of current respirators is viewed by many wearers as an equally cumbersome task. In order to remove the respirator, even for short periods, the lower strap must be unbuckled and the cradle lifted off the head as described herein above. A temporary removal, or parking, of the respirator is performed by slipping the cradle off the back of the head and allowing the facepiece to drop in front of the wearer wherein the respirator is supported by the lower strap around the neck of the wearer. Both the complete doffing and the parking of the respirator are further hampered by the inclusion of safety equipment as set forth herein above.
Another problem with prior art respirators results when respirators rely on upper straps having no elongation. Over time, latching of rigid straps causes material fatigue in the mask and may cause breakage of the mask during donning.
Another problem with prior art respirators is that the strap attachments, as well as tightening and release mechanisms, cause point loads in the facepiece making them uncomfortable to the wearer.
Accordingly, there remains a need in the art for a respirator that may be easily and conveniently donned, doffed and parked without discomfort to the wearer.
The above discussed and other drawbacks and deficiencies of the prior art are overcome or alleviated by the respirator headpiece and quick release mechanism of the present invention. The quick release mechanism uses an over center cam latch pivotably attached to a yoke to control the tension in an upper tension strap. In the latched position, the upper tension strap traverses the yoke, and together with a pair of lower straps, support and seal the respirator mask against the face of the wearer. In the unlatched position, the upper strap loosely supports the mask below the chin of the wearer in a parked position. The upper strap is attached to an arc shaped cradle or headpiece fitting to the top of the head of the wearer. The lower strap can be continuous or can comprise two straps mechanically secured behind the neck of the wearer. The lower, and more importantly, the upper straps preferably and advantageously comprise a material or materials having a low maximum elongation to ensure a snug and comfortable mask fit. Filter cartridges or sorbent and caps are optimized to provide easy replacement of filter elements or sorbent and maximal exposure of filter or sorbent material surface area.
The above discussed and other features and advantages of the present invention will be appreciated and understood by those skilled in the art from the following detailed description and drawings.